Electrical switch

ABSTRACT

An electrical switch assembly includes an insulating base carrying a plurality of electrical terminals having contacting surfaces thereon in coplanar relationship with raised surfaces of the base and further includes a shuttle member movable relative to the base which shuttle member carries a contacting element resiliently biased against raised surfaces of the base. The shuttle member has a tapered projection extending perpendicularly therefrom which projection is tightly captured in an aperture in the contacting element to prevent bodily shiftable movement of the contacting element relative to the shuttle member thereby preventing backlash in the switch assembly.

United States Patet [72] Inventors Willard E. Gracldy Anderson; Daniel W. Hyden, New Castle, both of, Ind. [21] Appl. No. 15,593 [22] Filed Mar. 2, 1970 [45] Patented Aug. 31,1971 [73] Assignee General Motors Corporation Detroit, Mich.

[54] ELECTRICAL SWITCH 4 Claims, 5 Drawing Figs.

[52] 11.8. C1 200/11 C, 200/11 J, 200/16 R [51] Int. Cl H01h19/58, HOlh 21/78, HOlh 15/00 [50] Field of Search IZOD/11,16, 11C,11J,16R,166CT [56] References Cited UNITED STATES PATENTS 3,019,308 1/1962 Ellithorpe 200/11 (.11

3,223,791 12/1965 Wanlass ZOO/16X 3,238,341 3/1966 Hayduw. 200/166 (BC) 3,255,319 6/1966 Paine 200/11 (.11)

Primary Examiner.l. R. Scott Atl0rneySW. E. Finken and D. L. Ellis v ABSTRACT: An electrical switch assembly includes an insulating. base carrying a plurality of electrical terminals having contacting surfaces thereon in coplanar relationship with raised surfaces of the base and further includes a shuttle member movable relative to the base which shuttle member carries a contacting element resiliently biased against raised surfaces of the base. The shuttle member has a tapered projection extending perpendicularly therefrom which projection is tightly captured in an aperture in the contacting element to prevent bodily shiftable movement of the contacting element relative to the shuttle member thereby preventing backlash in the switchassembly.

ELECTRICAL SWITCH-I This invention relates generally to electrical switches and in particular to means for preventing backlash within an electrical switch assembly.

Modern automotive type vehicles typically include rather complicated electrical systems, some components of which are designed to operate only when the vehicle is being operated in a particular mode. Common examples of this are backup lamps which must operate only when the vehicle transmission is placed in reverse range and engine cranking circuits which must be operable only when the vehicle transmission is in a nondriving range such as neutral. To accomplish these desired results, automotive electrical systems typically include switches having a plurality of fixed contacts and a movable shuttle member carrying a contacting element. The shuttle member is typically mechanically connected to the transmission selector such that for each position of the selector there is a corresponding position of the shuttle member and contacting element within the switch. The connection between the contacting element and the shuttle member, for various reasons, is typically of the floating type wherein springs bias the contacting element against the switch terminals with the shuttle member providing little or no lateral support for the contacting element. Without lateral support, movement of the shuttle member in response to movement of the transmission selector is followed by a certain amount of lost motion between the contacting element and shuttle member before corresponding movement of the contacting element begins due to the resilience of the springs between the shuttle member and the contacting element. The amount of lost motion or the backlash is directly dependent upon the amount of separation between the floating contacting element and the shuttle member. In an electrical switch assembly according to this invention means are provided which retain the advantages of the floating type suspension between the shuttle member and the contacting element but which prevent lost motion or backlash between the contacting element and the shuttle member upon movement of the latter.

The primary feature, then, of this invention is that it provides an improved electrical switch assembly including a base, a movable shuttle member, a contacting element, and means mounting the contacting element on the shuttle member which means prevent backlash or lost motion between the contacting element and the shuttle member. A further feature of this invention is that it provides mounting means for the contacting element including a tapered projection on one of the shuttle member and contacting element which projection is tightly engaged by gripping means on the other of the shuttle member and contacting element, such engagement preventing any bodily shiftable movement of the contacting element relative to the shuttle member.

Still further and more specific features of this invention reside in the provision of gripping means and a tapered projection which cooperate to permit limited rocking movement of the contacting element about a generally longitudinal axis of the shuttle member and in the provision of resilient means operable to bias the contacting element in one direction of rocking movement and into sliding engagement with the base. These and other features of this invention will be readily apparent from the following specification and from the drawings wherein:

FIG. I is a partially broken away view of a switch assembly according to this invention;

FIG. 2 is an enlarged sectional view taken generally along the plane indicated by lines 2-2 in FIG. 1;

FIG. 3 is an enlarged sectional view taken generally along the plane indicated by lines 3--3 in FIG. 2;

FIG. 4 is a sectional view taken generally along the. plane indicuted by lines 4-4 in FIG. 3; and

FIG. 5 is a sectional view taken generally along the plane indicated by lines 55 in FIG. 3.

Referring now to FIGS. 1 and 2 of the drawings, an electrical switch assembly according to this invention and generally designated 10 includes a generally triangular base 12 shrouded by a cover to be described hereinafter and fabricated from an electrical insulating type material, such as plastic or hard rubber, and having a gripping flange 14 extending therearound. Base 12 has a generally flat face 16 on which are formed three generally arcuate raised bearing surfaces 18, 20 and 22. The raised surfaces 18, 20 and 22 are recessed at various locations therealong to accommodate a plurality of generally flat contacting or electrically conductive surfaces 24, 26, 28 and 30 of a plurality of electrical terminals 32, 34, 36 and 38, respectively, fixedly secured to the base 12 with respective shank portions thereof projecting generally perpendicularly to the base on the side opposite flat face 16 and from within a protective circular flange 40, FIG. 2. A generally cylindrical hub 42 integral with the base 12 generally at the apex thereof includes an internal bore 44 having a plurality of angularly spaced raised ribs 46.

As seen best in FIG. 2, a generally rectangular shuttle member 48 with a top face 50 and a bottom face 52 has a generally cylindrical hub 54 integral therewith at one end. Hub 54 has a formed aperture 56 extending therethrough and the hub 54 is rotatably supported within bore 44 of the hub 42 on the base 12. The ribs 46 in hub 42 abut the end face of hub 54 on the shuttle member to position the top face 50 and the bottom face 52 thereof in generally parallel relationship to flat face 16 and the raised surfaces on the base. Generally midway between the ends of the shuttle member 38, bottom face 52 is relieved to provide an intermediate surface 58 substantially spaced above and parallel to both flat face l6 and raised sur faces 18, 20 and 22 on base 12.

The shuttle member 48 resiliently supports a pair of contacting elements movable generally as a unit with the shuttle member between a plurality of spaced positions wherein respective ones of the contacting elements electrically connect various ones of the contacting surfaces of the terminals. More particularly, with reference to FIGS. 2, 3 and 5, a generally U-shaped full floating contacting element 60 fabricated from an electrically conductive material, such as copper, and having a pair of locking barbs 62 at the ends thereof and a pair of spaced generally hemispherical projections 64 is mounted on the shuttle member for movement relative to the latter in a direction generally perpendicular to intermediate surface 58 with barbs 62 moving within respective ones of a pair of recesses 66 in the shuttle member, FIG. 5. As seen best in FIG. 3, the recesses 66 closely receive the upturned sides of contacting element 60 to prevent movement of the latter longitudinally of the shuttle member. The barbs 62 are engageable with the bottoms of the recesses 66 to limit downward movement of the contacting element relative to the shuttle member. A coil spring 68 seated in a cylindrical bore 70 in the shuttle member between recesses 66 bears against one side of the U-shaped contacting element to bias the latter away from the shuttle member, FIG. 5. In the mounted position of the shuttle member on the base, FIGS. 1 and 5, the hemispherical projections 64 on contacting element 60 slidingly engage raised surface 22 to compress spring 68. With the spring compressed the barbs 62 assume positions above the bottoms of the recesses 66 allowing the contacting element 60 a limited amount of movement or float relative to the shuttle member in a direction perpendicular to intermediate surface 58 while being resiliently maintained in sliding engagement with the raised surface 22 on the base 12.

As best seen in FIGS. 3 and 4, the shuttle member 48 has a pair of rectangular grooves 72 and 74 therein extending perpendicularly to intermediate surface 58. Rectangular groove 72 has a ledge 76. formed at the bottom thereof and rectangular groove 74 is spanned by a U-shaped support 78 projecting generally perpendicularly to intermediate surface 58. The bottom of the U-shaped support 78 is generally flat and forms a surface 80 coplanar with the bottom face 52 of the shuttle member. As best seen in FIG. 4, a conical tapered projection 82 integral with the U-shaped support extends perpendicularly to surface 80 on the side of the support opposite surface 80 faces 18 and 20 and balance projection 84 slidingly engages raised surface 18 to thereby maintain the top and bottom faces of the shuttle member in generally parallel relationship to front fact 16 of the base as the shuttle member moves relative to the base.

With particular reference now to FIGS 2, 3 and 4, a generally Y-shaped contacting element 86 fabricated from an electrically conductive material, such as copper, includes a flanged aperture 88, a circular convexly flanged aperture 90,

an upturned tab 92 with a locking barb 94 thereon, an offset tail 96 and a pair of generally hemispherical projections 98. As best seen in FIG. 4, the offset tail 96 projects into rectangular groove 74 and the tapered projection 82 is captured by the circular aperture 90 generally on the convex flange of the latter. With the convex flange of circular aperture 90 firmly seated on the tapered projection, bodily shiftable movement of the contacting element 86 relative to the shuttle'member in a plane generally parallel to intermediate surface 7 8 is prevented so that the contacting element is unitarily movable with the shuttle member relative to the base. The contacting" element 86 is, however rotatable relative to the shuttle member in a plane generally parallel to intermediate surface 58 about the vertical axis of the conical tapered projection 82. To restrict such rotary movement the upturned tab 92is closely received within rectangular groove 72, FIG. 3. 7

While being restricted against bodily shiftable and rotary movement relative to the shuttle member as described, the engagement between the tapered projection 82 and the convex flange of the aperture 90, FIG. 4, permits limited rocking movement of the contacting element relative to he shuttle member about a longitudinal axis thereof extending through the tapered projection. The limit of such rocking movement in a clockwise direction, FIG. 4, is determined by the length of upturned tab 92 the barbed portion 94 of which engages ledge 76 to halt such rocking movement and prevent separation of the contacting element from the shuttle member. In the counterclockwise direction, intermediate surface 58 providesthe limit for rocking movement of the contacting element. A coil spring 100 having one end seated in a cylindrical bore 102 in the shuttle member, bears at the other end on the contacting element 86 around aperture 88 to bias the contacting element clockwise, FIG. 4, toward the aforementioned limit position of rocking movement.

In the mounted position of the shuttle member on the base, FIGS. 1, 2 and 4, the contacting element 86 spans the distance between raised surfaces 18 and 20 on the base and respective ones of the hemispherical projections 98 slidingly engage raised surfaces 18 and 20. The raised surfaces function to maintain the contacting element in a position intermediate the limits of rocking movement, FIG. 4, wherein the spring 100 is compressed. With the spring compressed the convex flange of aperture 90 is maintained firmly seated on the tapered projection 82 while barb 94 on upturned tab 92 assumes a position above ledge 76 allowing the contacting element 86 a limited amount of rocking or semifloating movement relative to the shuttle member about a longitudinal axis of the latter through V the tapered, projection while being resiliently maintained in sliding engagement with raised surfaces 18 and 20.

As best seen in FIGS. 1 and 2, a generally triangular cover I04 having an indentation [06 extending arcuately thereacross, a generally circular aperture 108 at the apex thereof and a flange 110 extending completely therearound is mounted on base 12 completely shrouding the base and shut tle member 48 except for a portion of cylindrical hub 54 extending through aperture 108. The flange 110 of the cover 104 is crimped over flange 14 of the base 12 to rigidly secure the cover to the base. In the secured position of the cover, indentation 106 abuts the top face 50 of the shuttle member and maintains the surface of U-shaped support 78 and the balance projection 84 in engagement with the arcuate raised surfaces 18 and 20 on the base, FIG. 2. The shuttle member is thereby maintained in generally parallel relationship to the flat face I6 of the base while being rotatable about an axis of the latter extending generally perpendicularly thereto.

The switch assembly according to this invention, when incorporated into the backup lamp and engine cranking circuits of a typical automobile is normally fixedly secured to the vehicle body by conventional means, not shown, with link means, not shown, rigidly connecting the vehicle transmission selector to the aperture 56 inthe shuttle member 48 such that transmission controlling movement of the selector initiates rotation of the shuttle member 48 relative to the base 12 between a plurality of spaced positions. When the vehicle 7 cle backup lamps and are electrically connected together by contacting element 60 only when the vehicle transmission is placed in the reverse range. More particularly, the contacting surfaces 28 and 30, lying in coplanar relationship with raised surface 22, are spaced apart a distance generally equal to the spacing between hemispherical projections 64 on contacting element 60. Further, the terminals 36 and 38 are situated on the base 12 in a predetermined location such that only when the shuttle member assumes the angular position R, FIG. 1, corresponding to thetransmission reverse range will the con tacting element 60-electrically connect the contacting surfaces 28 and 30 to complete the backup lamp circuit. In any angular position of v the shuttle member other than that designated R, one or both of the projections 64 will rest on a portion of electrically insulating raised surface 22 thereby opening the backup lamp circuit to prevent illumination of the backup lamps.

As seen best in FIGS. 3 and 5, initial movement of the shuttle member resultsin backlash or lost motion between contacting element 60 and the shuttle member because of the resilience of coil spring 68. As a maximum, the lost motion may persist until one side of the shuttle member abuts one upstanding side of the U-shaped contacting element and forces sliding movement thereof over raised surface 22.

Cranking of the engine of the vehicle through the starter mechanism and starting motor is normally desirable only if the vehicle transmission is in a nondriving range such as neutral or park. To insure such sequencing, the terminals 32 and 34 are wired in series in the engine starting motor circuit such that only when the terminals 32 and 34 are electrically connected can the engine be cranked by the starting motor through the starter mechanism. More particularly, referring to FIGS. 1, 3 and 4, the contacting surfaces 24 and 26 of the terminals 32 and 34, lying in coplanar relationship with the raised surfaces 18 and 20 of the base, are spaced apart at two locations a distance generally equal to the spacing between raised surfaces IIS and 20 which distance is generally equal to the distance between hemispherical projections 98 on the contacting element 86. Further, the terminals 32 and 34 and their respective contacting surfaces are situated on the base 12 in prevents bodily shiftable movement of the contacting element relative to the shuttle member, as described hereinbefore, so that backlash is effectively eliminated. The rectangular groove 72, closely receiving tab 92 on the contacting element 86, prevents rotary movement of the contacting element relative to the shuttle member so that the spring 100 is operable to maintain respective ones of the hemispherical projections 98 slidably engaged with raised surfaces 18 and 20. There is, therefore, virtually instantaneous movement of both the shuttle member 48 and contacting element 86 in response to transmission controlling movement of the selector and thus no lost motion or backlash between the contacting element and shuttle member.

It will, of course, be apparent to those skilled in the art that means other than a conical tapered projection and circular aperture could be employed to prevent backlash or lost motion between the contacting element and the shuttle member. One example of an alternative arrangement would include a square aperture in the contacting element engaging a polyhedral projection on the shuttle member having a square base and four triangular sides meeting at a common vertex. In this example it is apparent that tight engagement between the tapered projection and the aperture prevents both bodily shiftable movement and rotary movement of the contacting element relative to the base while again permitting the desirable rocking movement.

Having thus described the invention, what is claimed is:

1. An electrical switch assembly comprising in combination, a base having a plurality of electrical terminals defining a plurality of spaced electrically insulated contacting surfaces, a shuttle member, means mounting said shuttle member on said base for movement relative thereto in two opposite directions between a plurality of spaced positions corresponding to the spacing of said contacting surfaces, a contacting element, a tapered projection on one of said shuttle member and said contacting element, means on the other of said shuttle member and said contacting element engaged on said tapered projection to thereby mount said contacting element on said shuttle member for lash-free unitary movement therewith and for limited rocking movement relative thereto in two opposite directions about an axis of said shuttle member through said tapered projection, and resilient means operable to bias said contacting element in one of said two opposite directions of rocking movement, said resilient means with said shuttle member mounted on said base maintaining said contacting element in sliding engagement with said base and said contacting element upon lash-free unitary movement with said shuttle member between said plurality of spaced positions being operable to contact and electrically connect various ones of said contacting surfaces.

2. An electrical switch assembly comprising in combination, a base having a plurality of electrical terminals defining a plurality of spaced electrically insulated contacting surfaces, a shuttle member, means mounting said shuttle member on said base for movement relative thereto in two opposite directions between a plurality of spaced positions corresponding to the spacing of said contacting surfaces, a contacting element, a tapered projection on one of said shuttle member and said contacting element extending generally perpendicularly thereto and being generally circular in cross section, means on the other of said shuttle member and said contacting element engaged on said tapered projection to thereby mount said contacting element on said shuttle member for lash-free unitary movement with said shuttle member and for rotary and limited rocking movement relative to said shuttle member respectively about a first axis defined by said tapered projection and perpendicular to said shuttle member and a second axis extending generally perpendicularly to said first axis, means on said shuttle member and said contacting element operable to substantially restrict said rotary movement of said contacting element relative to said shuttle member, and resilient means operable to bias said contacting element in one direction of rocking movement, said resilient means with said shuttle member mounted on said base maintaining said contacting element in sliding engagement with said base, and said contacting element upon said lash-free unitary movement with said shuttle member between said plurality of spaced positions being operable to contact and electrically connect various ones of said contacting surfaces.

3. An electrical switch assembly comprising in combination a base having a plurality of electrical terminals defining a plurality of spaced electrically insulated contacting surfaces, a shuttle member having a generally conical tapered projection extending perpendicularly thereto, means mounting said shuttle member on said base for movement relative thereto in two opposite directions between a plurality of spaced positions corresponding to the spacing of said contacting surfaces, a contacting element having a generally circular convexly flanged aperture therein, said conical projection on said shuttle member being captured by said circular aperture generally on said convex flange thereof to thereby mount said contacting element on said shuttle member for lash-free unitary movement with said shuttle member and for rotary and limited rocking movement relative to said shuttle member respectively about the axis of said conical tapered projection and an axis extending generally perpendicularly thereto, means on said shuttle member and said contacting element operable to substantially restrict said rotary movement of said contacting element relative to said shuttle member, and resilient means operable to bias said contacting element in one direction of rocking movement, said resilient means with said shuttle member mounted on said base maintaining said contacting element in sliding engagement with base, and said contacting element upon lash-free unitary movement with said shuttle member between said plurality of spaced positions being operable to contact and electrically connect various ones of said contacting surfaces.

4. An electrical switch assembly comprising in combination, a base having a plurality of raised surfaces and carrying a plurality of electrical terminals defining a plurality of electrically insulated contacting surfaces situated in generally coplanar relationship with said raised surfaces, a shuttle member having a recess therein and a generally conical tapered projection extending perpendicularly to said shuttle member, means mounting said shuttle member on said base for movement relative thereto in two opposite directions between a plurality of spaced positions corresponding to the spacing of said contacting surfaces, a contacting element having 'a generally circular convexly flanged aperture therein at one end thereof and an upturned tab at the other end thereof, said conical projection being captured by said circular aperture on said convex flange of the latter to thereby mount said contacting element on said shuttle member for lash-free unitary movement with said shuttle member and for rotary and limited rocking movement relative to said shuttle member respectively about the axis of said conical tapered projection and an axis extending generally perpendicularly thereto, said upturned tab on said contacting element being closely received within said recess on said shuttle member to substantially restrict said rotary movement of said contacting element relative to said shuttle member, and a spring bearing at one end against said shuttle member and at the other end against said contacting element at a location on the latter between said convexly flanged circular aperture and said upturned tab, said spring biasing said contacting element in one direction of rocking movement so that with said shuttle member mounted on said base said contacting element is resiliently maintained sliding engagement with said raised surfaces, said contacting element upon said lash-free unitary movement with said shuttle member between said plurality of spaced positions being operable to contact and electrically connect various ones of said contacting surfaces. 

1. An electrical switch assembly comprising in combination, a base having a plurality of electrical terminals defining a plurality of spaced electrIcally insulated contacting surfaces, a shuttle member, means mounting said shuttle member on said base for movement relative thereto in two opposite directions between a plurality of spaced positions corresponding to the spacing of said contacting surfaces, a contacting element, a tapered projection on one of said shuttle member and said contacting element, means on the other of said shuttle member and said contacting element engaged on said tapered projection to thereby mount said contacting element on said shuttle member for lashfree unitary movement therewith and for limited rocking movement relative thereto in two opposite directions about an axis of said shuttle member through said tapered projection, and resilient means operable to bias said contacting element in one of said two opposite directions of rocking movement, said resilient means with said shuttle member mounted on said base maintaining said contacting element in sliding engagement with said base and said contacting element upon lash-free unitary movement with said shuttle member between said plurality of spaced positions being operable to contact and electrically connect various ones of said contacting surfaces.
 2. An electrical switch assembly comprising in combination, a base having a plurality of electrical terminals defining a plurality of spaced electrically insulated contacting surfaces, a shuttle member, means mounting said shuttle member on said base for movement relative thereto in two opposite directions between a plurality of spaced positions corresponding to the spacing of said contacting surfaces, a contacting element, a tapered projection on one of said shuttle member and said contacting element extending generally perpendicularly thereto and being generally circular in cross section, means on the other of said shuttle member and said contacting element engaged on said tapered projection to thereby mount said contacting element on said shuttle member for lash-free unitary movement with said shuttle member and for rotary and limited rocking movement relative to said shuttle member respectively about a first axis defined by said tapered projection and perpendicular to said shuttle member and a second axis extending generally perpendicularly to said first axis, means on said shuttle member and said contacting element operable to substantially restrict said rotary movement of said contacting element relative to said shuttle member, and resilient means operable to bias said contacting element in one direction of rocking movement, said resilient means with said shuttle member mounted on said base maintaining said contacting element in sliding engagement with said base, and said contacting element upon said lash-free unitary movement with said shuttle member between said plurality of spaced positions being operable to contact and electrically connect various ones of said contacting surfaces.
 3. An electrical switch assembly comprising in combination a base having a plurality of electrical terminals defining a plurality of spaced electrically insulated contacting surfaces, a shuttle member having a generally conical tapered projection extending perpendicularly thereto, means mounting said shuttle member on said base for movement relative thereto in two opposite directions between a plurality of spaced positions corresponding to the spacing of said contacting surfaces, a contacting element having a generally circular convexly flanged aperture therein, said conical projection on said shuttle member being captured by said circular aperture generally on said convex flange thereof to thereby mount said contacting element on said shuttle member for lash-free unitary movement with said shuttle member and for rotary and limited rocking movement relative to said shuttle member respectively about the axis of said conical tapered projection and an axis extending generally perpendicularly thereto, means on said shuttle member and said contacting element operable to substantially restrict said rotary movement of said contacting element relative to said shuttle member, and resilient means operable to bias said contacting element in one direction of rocking movement, said resilient means with said shuttle member mounted on said base maintaining said contacting element in sliding engagement with base, and said contacting element upon lash-free unitary movement with said shuttle member between said plurality of spaced positions being operable to contact and electrically connect various ones of said contacting surfaces.
 4. An electrical switch assembly comprising in combination, a base having a plurality of raised surfaces and carrying a plurality of electrical terminals defining a plurality of electrically insulated contacting surfaces situated in generally coplanar relationship with said raised surfaces, a shuttle member having a recess therein and a generally conical tapered projection extending perpendicularly to said shuttle member, means mounting said shuttle member on said base for movement relative thereto in two opposite directions between a plurality of spaced positions corresponding to the spacing of said contacting surfaces, a contacting element having a generally circular convexly flanged aperture therein at one end thereof and an upturned tab at the other end thereof, said conical projection being captured by said circular aperture on said convex flange of the latter to thereby mount said contacting element on said shuttle member for lash-free unitary movement with said shuttle member and for rotary and limited rocking movement relative to said shuttle member respectively about the axis of said conical tapered projection and an axis extending generally perpendicularly thereto, said upturned tab on said contacting element being closely received within said recess on said shuttle member to substantially restrict said rotary movement of said contacting element relative to said shuttle member, and a spring bearing at one end against said shuttle member and at the other end against said contacting element at a location on the latter between said convexly flanged circular aperture and said upturned tab, said spring biasing said contacting element in one direction of rocking movement so that with said shuttle member mounted on said base said contacting element is resiliently maintained sliding engagement with said raised surfaces, said contacting element upon said lash-free unitary movement with said shuttle member between said plurality of spaced positions being operable to contact and electrically connect various ones of said contacting surfaces. 